JOLIET, Ill. (AP)  The suffocation death of a 1½-year-old girl, whose body was found underneath a couch in her suburban Chicago home after she”d been reported missing, has been ruled a homicide, a coroner”s office announced Friday.

Semaj Crosby was found dead on April 27 in a Joliet Township home shortly after the Department of Children and Family Services closed an investigation into whether she was being neglected. DCFS officials later said social workers saw no hazards or safety concerns.

Semaj”s died of asphyxia, or suffocation, according to the coroner”s office, which said it considered in its findings the circumstances of her death, DCFS reports, a police investigation, photographs from the scene and autopsy results.

The office also pointed to the “unusual circumstances surrounding her disappearance and the subsequent discovery of her decomposing body under the couch in her home.” Those unusual circumstances include a suspicious fire that later burned down the home where Semaj and her three older brothers lived with their mother and a collection of squatters, and the lack of cooperation from witnesses.

Hundreds of police and volunteers searched for the girl after she was reported missing. She was found the next day in the house, which had been searched by authorities. Days later, and after it had been deemed uninhabitable by authorities, the house burned down in what authorities say was arson.

Spokesman Charles B. Pelkie said both the Will County state”s attorney”s office and the sheriff”s office are searching for answers.

“This case is highly sensitive and a top priority for the state”s attorney”s office and the sheriff”s office,” Pelkie said. “We”re working vigorously on it and no resources are being spared.”